GasBuddy, the nation’s leading gas price app, congratulates the top 25 lowest priced retail gasoline offerings, which together saved consumers millions of dollars on their yearly gasoline fill-ups in 2013.

Each year, GasBuddy combs through nearly 35 million individual gasoline prices and compares each brand’s pump offering (by zip code) to the average price of local competitors. It then tabulates the results, rating each brand by the average discount it delivered versus the average pump prices in its competitive area.

For the second year in a row, Costco was the undisputed leader in value pricing. The average Costco on any given day in 2013 was priced more than 14cts gal lower than competitors. That 2013 discount was nearly 10 percent more aggressive than the 12.84 cts gal Costco delivered in savings versus competitors in 2012.

Western multistate marketer ARCO came in second, with an average daily station discount versus competitors of 13.5 cents gal, some 8.5 percent more aggressive than the price differential in 2012. ARCO was the only traditional gasoline retailer to make it to GasBuddy’s Top 25 list this year. Seven chains that made the Top 25 ranking were primarily supermarkets or supercenters, including Fred Meyer which yielded a discount of more than 10cts gal. Other grocers in the group included Smiths which typically sold at 6.2 cents gal under competitors, followed by Safeway, Stop & Shop, Kroger, H-E-B, and Frys, all of which had average discounts in 2013 of more than 4 cents gal.

The other two Big Box clubs, Sam’s and BJ’s, were ranked 5th and 6th in the GasBuddy tally, with respective discounts that were 10.1 cents gal and 9.3 cents gal below local rivals. Northern California based Quick Stop was the most aggressive traditional convenience store, taking the bronze number three slot among marketers that had the 50 sites necessary to qualify for the ranking. Quick Stop priced its stations some 12.5 cents gal below competitors.

“We applaud these chains who clearly do their best to keep gas prices low for consumers,” said GasBuddy founder, Jason Toews. “Our goal at GasBuddy is to help consumers save money when buying fuel, and identifying the consistently cheapest sites is a key step.”

More than 35 million consumers have downloaded the free GasBuddy App, which allows motorists to find the cheapest gas stations in any area of the U.S. or Canada by simply pushing a button.

To get the complete list of the 25 most aggressive fuel chains and Top 5 for each state point your browser to http://bit.ly/1b3zKrn

Methodology: GasBuddy compared the daily average of every chain in the U.S. by zip code to the average of the other stations in that zip code. A difference is calculated each day for each zip code and that differential is rolled up to the Country and each state for the entire year. Note: If a retailer is in an area where most stores don’t match their prices they will have a larger differential. Conversely, if a retailer is in a very competitive area and all stations price very closely to one another, that retailer will show a smaller differential. GasBuddy reminds everyone that station prices change often and encourages drivers to shop around by using the GasBuddy app everyday to find the best bargains. To make the national Top25 list a retailer had to have at least 50 stores. At the state level, each chain needed to have at least 10 sites to qualify.